Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

"Edible Optics" Could Make Food Safer

08.08.2008
Tufts University scientists have shown that it is possible to design biologically active, biodegradable optical devices – made from silk and needing no refrigeration - with applications in medicine, health, the environment and communications. For example, edible optical sensors could detect harmful bacteria in produce, and be consumed right along with the food if it were safe.

Imagine an edible optical sensor that could be placed in produce bags to detect harmful levels of bacteria and consumed right along with the veggies. Or an implantable device that would monitor glucose in your blood for a year, then dissolve.

Scientists at Tufts University's School of Engineering have demonstrated for the first time that it is possible to design such "living" optical elements that could enable an entirely new class of sensors. These sensors would combine sophisticated nanoscale optics with biological readout functions, be biocompatible and biodegradable, and be manufactured and stored at room temperatures without use of toxic chemicals. The Tufts team used fibers from silkworms to develop the platform devices.

Tufts University has filed a number of patent applications on silk-based optics and is actively exploring commercialization opportunities.

... more about:
»Biomedical »Quality »Sensor »biodegradable

"Sophisticated optical devices that are mechanically robust yet fully biodegradable, biocompatible and implantable don't exist today," said principal investigator Fiorenzo Omenetto, associate professor of biomedical engineering and associate professor of physics. "Such systems would greatly expand the use of current optical technologies in areas like human and livestock health, environmental monitoring and food quality."

"For example, at a low cost, we could potentially put a bioactive silk film in every bag of spinach, and it could give the consumer a readout of whether or not E. coli bacteria were in the bag—before the food was consumed," explained David Kaplan, professor and chair of the biomedical engineering department.

The Tufts research was published in a recent paper in Biomacromolecules by Brian D. Lawrence, graduate student in biomedical engineering; Mark Cronin-Golomb, associate professor, biomedical engineering; Irene Georgakoudi, assistant professor, biomedical engineering; Kaplan, and Omenetto.

(http://pubs.acs.org/cgi-bin/article.cgi/bomaf6/2008/9/i04/pdf/bm701235f.pdf).

Optics – the science of light and its interaction with matter – has fascinated generations of scientists such as Sir Isaac Newton. Current optical device platforms are based primarily on glass, semiconductors, plastics or polymers. But the harsh solvents and extreme temperatures needed for manufacture make it impossible to incorporate bioactive sensing components into the devices. Chemical residues and lack of biodegradability also limit environmental and medical applications. Furthermore, biological components typically need to be stored at controlled temperatures to retain their activity.

The possibility of integrating optical readout and biological function in a single biocompatible device unconstrained by these limitations is tantalizing. Silk optics has captured the interest of the Defense Department, which has funded and been instrumental in enabling rapid progress on the topic. The Defense Advanced Research Projects Agency (DARPA) awarded Tufts a research contract in 2007 and is funding Tufts and others on groundbreaking projects that could someday result in biodegradable optical sensing communications technology.

Silk a Natural for Biocompatible Optics
Silk proteins are, literally, a natural for integrating optical and biological functions. They can be processed in water at ordinary temperatures and patterned on the nanoscale to generate a wide range of optical elements, including ultrathin films, thick films, and nanoscale and large-diameter fibers. Silk proteins also offer excellent surface quality and transparency, which are perquisites for high-quality optics. Equally important, they are mechanically robust.

"Silks spun by spiders and silkworms represent the strongest and toughest natural fibers known. They offer many opportunities for functionalization, processing and biological integration when compared to conventional polymers," said Kaplan, an expert on natural biomaterials like silk.

To form the devices, Tufts scientists boiled cocoons of the Bombyx mori silkworm in a water solution and extracted the glue-like sericin proteins. The purified silk protein solution was ultimately poured onto negative molds of ruled and holographic diffraction gratings with spacing as fine as 3600 grooves/mm. The cast silk solution was air dried to create solid fibroin silk films that were cured in water, dried and optically evaluated. A similar process was followed to create lenses, microlens arrays and holograms. Film thicknesses from 10 to 100 µm were characterized for transparency and optical quality.

The variety and quality of the optical elements compared favorably with conventional platforms and outperformed other commonly used biopolymers.

However, the most compelling feature of the platform, according to the Tufts researchers, is that the elements are prepared, processed and optimized in all-aqueous environments and at ambient temperature. This makes possible the inclusion of sensitive biological 'receptors' within the solution that stay active after the solution has hardened into a free-standing silk optical element.

No Refrigeration Needed
The Tufts team embedded three very different biological agents in the silk solution: a protein (hemoglobin), an enzyme (horseradish peroxidase) and an organic pH indicator (phenol red). In the hardened silk optical element, all three agents maintained their activity for long periods when simply stored on a shelf. "We have optical devices embedded with enzymes that are still active after almost a year of storage at room temperature. This is amazing given that the same enzyme becomes inactive if forgotten and left unrefrigerated for a few days," said Omenetto."

Researchers also found that it was possible to alter the propagation of light through the silk optic as a function of the embedded dopant to create an optical signal of the biological activity.

Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.

Kim Thurler | Newswise Science News
Further information:
http://www.tufts.edu

Further reports about: Biomedical Quality Sensor biodegradable

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>